ES2287086T3 - MEDICAL TELEMETRY SYSTEM. - Google Patents

Abstract

A telemetric medical system (30), comprising: a telemetric medical sensor (50) for implantation in the body of a patient for the measurement of a parameter therein, the sensor comprising a housing (52), a membrane (56 ) at one end of the housing, the deformable membrane being in response to the parameter, and a microchip (90) positioned inside the housing (52) and operatively communicating with the membrane to transmit a signal indicative of the parameter, and a device ( 140) for reading and loading a positionable signal outside the body of a patient for communication with the sensor (50), the reading and signal loading device (140) comprising a housing (145); and a circuit (150) inside the housing, the circuit comprising a logic control unit (154) for sending a power signal to the sensor (50) to remotely power the sensor, and also for receiving said unit (154) control logic the signal transmitted from the sensor (50), in which the signal transmitted by the sensor (50) is a digital signal, in which the microchip (90) comprises an array (92) of photoelectric cells (95) , the system further comprising an LED (100) for transmitting light to the photoelectric cells (95), characterized in that the circuit (150) further comprises a processing unit (170) operatively connected to the control unit (154) for converting the signal transmitted by the sensor (50) into the measured parameter, in which the sensor (50) further comprises a shutter (62) connected to the membrane (56) and movable between the photoelectric cells (95) and the LED ( 100) in response to the deformation of the me Mbrana

Description

Medical telemetry system.

Field of the Invention

The present invention relates, in general, to telemetric medical devices More particularly, the present invention refers to a novel telemetric medical system that is susceptible of various medical applications including measurement of a parameter inside a patient's body, in particular an organ. Such an application of this invention, consists of an endocardiac pressure system Implantable telemetric, its associated novel components, and its novel methods of use.

Background of the invention

In general, the use of implantable medical sensors in a patient is known. An example of an implantable sensor is described in US Patent No. 4,815,469 (Cohen et al .). The description is directed to an implantable medical sensor that determines the oxygen content of the blood. The sensor includes a miniature hybrid circuit that includes light emitting diode means, phototransistor means, and a substrate with which the light emitting diode means and phototransistor means are linked to a desired circuit configuration. The hybrid circuit is hermetically sealed inside a cylindrical body made of a material that is substantially transparent to light, such as glass. Through power terminals provide means to make an electrical connection to the hybrid circuit. The light emitting diode means are excited by a step current pulse. The objective of the sensor is to detect the reflective properties of a body fluid, such as blood, for spectrophotometric analysis. In one embodiment, the sensor is embedded inside a bilumen pacemaker driver, and positioned near the driver's distal electrode so that the sensor resides inside the heart when the driver is implanted into a patient, thereby allowing the Blood oxygen content detected inside the heart constitutes a physiological parameter that can be used to control the range of a range response pacemaker.

US Patent No. 5,353,800 (Pahndorf et al .), Describes an implantable pressure sensor conductor, which has a hollow needle adapted to be screwed into the heart of a patient. The pressure sensor is powered by electrical power through conductors present in the sensor.

There are cases in which permanent sensor positioning is required. One such case, for example, is described in US Patent No. 5,404,877 (Nolan et al .). An implantable cardiac arrhythmia alarm without a driver is described, which continuously evaluates the function of a patient's heart, to discriminate between normal and abnormal functioning of the heart and, upon detection of an abnormal condition, generates a warning signal to the patient. The alarm is capable of detecting measurements of impedance of the heart, breathing and movement of the patient and, from these measurements, generate an alarm signal when the measurements indicate the occurrence of a cardiac arrhythmia. It is important to note that the sensor uses an antenna system that has a coil inductor to generate an electromagnetic field in the tissue for the detection of impedance changes that are related to physiological phenomena. For example, the size of the inductor is pre-selected so that it matches the dimensions of the organ or structure to be measured.

There are also several known implantable devices that use telemetry to transmit or receive data from an external device. Such a device consists, for example, of the system described in US Patent No. 6,021,352 (Christopherson et al .). The device uses a pressure sensor as a transducer to detect the patient's respiratory effort. The respiratory waveform information is received by an implantable pulse generator (IPG) simulator from a transducer, and a synchronous inspiration simulation is provided by the IPG.

Another implantable telemetric device is described in US Patent No. 5,999,857 (Weijand et al .). This reference describes a telemetry system for use with implantable devices such as cardiac pacemakers and the like, for two-way telemetry between the implanted device and an external programmer. The system employs oscillator and encoder circuits for synchronous transmission of data symbols, where the symbols form the telemetry carrier. The system provides circuits for higher density data encoding of sinusoidal symbols, including combinations of BPSK, FSK and ASK encoding. Transmitter embodiments for both the implant device and the external programmer, as well as the modulator and demodulator circuits, are also described. It is important to note that an implant device has its own power supply in the form of a battery for the supply of all the circuitry and the components of the implanted device.

In US 5,833,603, a telemetric medical system of the type defined in the preamble of the accompanying claim 1.

It is also important to appreciate that, until the date, there is no telemetric medical system that is both a highly efficient system because of its components, and easy to use while providing extremely information precise in relation to a parameter measured in the body of a patient.

Summary of the invention

The present invention is directed to a novel telemetric medical system for use with various medical applications such as medical conditions of monitoring or measurement of parameters inside the body of a patient for different types of organs, including the tissue, as well as its function.

The present invention is a medical system telemetric comprising a telemetric medical sensor for its implantation in the body of a patient, for the measurement of a parameter in it. The sensor comprises a housing, in the that the membrane is deformable in response to the parameter. A microprocessor, which takes the form of a microchip, is found located inside the accommodation and communicates operatively with  the membrane for the transmission of a signal indicative of parameter. The signal transmitted by the sensor is a signal digital.

The system also comprises a device for signal reading and load that is positionable outside the body of the patient for communication with the sensor. The device of signal reading and loading comprises a housing and a circuit in the inside the housing. The circuit comprises a logical unit of control and a processing unit operatively connected to the logical control unit. The logical control unit has been intended for sending a power signal to the sensor, optionally through a connected sine wave exciter Operationally to the control unit, for remote power of the sensor. The logical control unit is also intended for receive, optionally through a deep detector, the signal transmitted from the sensor. The processing unit is operatively connected to the logical control unit for convert the transmitted signal into the measured parameter.

The power signal can be a signal of sine wave of approximately 4 - 6 MHz. The unit of Processing may include a connected power supply operationally to the circuit, and a power switch for Activate and deactivate the device.

The device for reading and signal loading, It can also include an antenna coil to send the signal of power to the sensor and to receive the transmitted digital signal from the sensor. The reading and signal loading device can also include a display, which can be an LCD screen, for displaying the measured parameter. Preferably, the Processing unit decodes the transmitted signal.

The microprocessor, which takes the form of microchip, comprises an array of photoelectric cells that can  Be arranged by stacked rows. The matrix can include also a reference photoelectric cell located in a matrix end. A light emitting diode (LED) transmits light to photoelectric cells and, when the matrix includes a cell reference photoelectric, to the photoelectric cell of reference.

The sensor further comprises a shutter connected to the membrane and mobile between photoelectric cells and the LED in response to the deformation of the membrane. The sensor can be arranged such that the photoelectric cell of reference is not locked by the shutter and remains exposed to the light emitted by the LED.

The microchip can also comprise a plurality of comparators operatively connected to the cells photoelectric and a buffer memory operatively connected to the comparators for storing and transmitting the digital signal. A buffer can be operatively connected to comparators to store and transmit the signal. The sensor can further comprise an antenna, coil-shaped, connected operationally to the microchip, in which the antenna is located outside of accommodation. Alternatively, the antenna may be located in the inside of the sensor housing.

The present invention may be better from the detailed description that follows from the preferred embodiments thereof, taken together with the drawings, in which:

Brief description of the drawings

Figure 1 is a schematic illustration of a implantable telemetric medical sensor in accordance with this invention;

Figure 2 is a top view of the sensor of Figure 1;

Figure 3 is a schematic illustration of an alternative embodiment of the sensor of Figure 1, which has a tapered distal end with helical threads and tip of tissue perforation, for anchoring in the tissue;

Figure 4 is another alternative embodiment of sensor of Figure 1 having a tapered distal end with tip of tissue perforation and a plurality of piercing spikes in the same;

Figure 5 is a partial perspective view of the sensor of Figure 1 with some parts removed for the purpose of expose the internal components of the sensor;

Figure 6A is a schematic diagram that illustrates a microprocessor circuit for the sensor according to the present invention;

Figure 6B is a schematic diagram that illustrates a logic circuit for the microprocessor circuit of the Figure 6A;

Figure 7 is a schematic illustration that represents a matrix of photoelectric cells for the sensor according to the present invention;

Figure 8 is a schematic illustration that represents the telemetric system in accordance with this invention, including the sensor of Figure 1 and a device of signal reading and loading, located in remote position of, and in communication with the sensor;

Figure 9 is a schematic diagram that illustrates a read / load circuit for the reading device  and signal load of Figure 8;

Figure 10 is a schematic illustration of the heart of a patient, and

Figure 11 is a schematic illustration that represents the sensor fully deployed inside a tissue opening, in accordance with the present invention.

Description of preferred embodiments

The present invention relates to a novel telemetric medical system 30, as illustrated in Figure 8, as well as its innovative components and use procedures, useful for various medical applications, as explained and demonstrated at the moment.

An aspect of the system 30 of the present invention consists of remotely detecting and measuring a characteristic or parameter (or a number of different parameters, including the magnitude of any parameter), inside the body of a patient, or within an organ or body tissue of the patient, by using a novel medical 50 sensor Implantable telemetric, which is fully wireless, and a charging device 140 operatively communicating with the sensor fifty.

Telemetric Sensor

As schematically illustrated in Figure 1, the sensor 50 comprises a housing 52 made of a biocompatible material such as poly-silicon or titanium. The housing 52 preferably has a cylindrical shape, although any shape is acceptable for the housing 52. The housing 52 has an approximate length in the range of 4-5 mm, and an approximate diameter in the range of 2.5 - 3 mm The housing 52 may also be smaller, for example 3 mm in length and 1-2 mm in external diameter. Housing 52 includes cylindrical walls that are approximately 250 µm thick. A flexible membrane 56, made of a deformable material, is fixed with one end of the housing 52. A notch 58 and a circumferential groove 60 have been provided on the outer surface of the housing 52 to facilitate feeding and implantation of the housing.
sensor 50.

The membrane 56 is made of a material flexible or deformable, such as poly-silicon rubber or polyurethane. The membrane 56 has an approximate thickness of 20 um and has a diameter in the range of approximately  1.5 - 2 mm The membrane 56 is normally pushed out of housing 52 due to the internal pressure existing in the housing 52. Membrane 56 is forced to merge towards the inside the housing 52 provided the external pressure at housing 52 exceeds the internal pressure inside of accommodation 52.

Since the membrane 56 is deformable and normally it is pushed out of the housing 52, the membrane 56 responds directly to the environment of the tissue or the organ that is being monitored and / or measured as to a particular characteristic or parameter. In response even to lighter changes in these characteristics or parameters, the membrane 56 deforms into the housing 52. In Consequently, there is a direct relationship or correspondence between any change in the characteristic or parameter measured and the amount or degree of deforming action or membrane movement 56.

It is important to appreciate that membrane 56 has an area of relatively large dimension when compared to solid state membrane devices, such as sensors piezoelectric or manufactured memory chips that use membranes Consequently, the electronics requirements of the 50 sensor are less demanding. Additionally, membrane 56 has a deflection much larger than that of the state membrane solid.

The sensor 50 also includes a coil 68 of antenna that is operatively connected to the internal components of the sensor 50 by means of an antenna cable 70. The antenna 68 is an inductance coil that has a coil configuration in spiral. The material used for the antenna wire has a content of approximately 90% silver with a coating of platinum - iridium with a content of approximately 10%. The antenna coil 68 is preferably made with 20-25 turns of 30 µm thick thread. He external diameter of the antenna is 1.5 - 2.0 cm (Figure 2).

Consequently, due to these characteristics, The antenna coil 68 has a very low parasitic capacitance. Additionally, the antenna coil 68, due to the content of silver / platinum of its thread, has an extremely conductivity High and is extremely flexible.

Although antenna 68 is described as external to accommodation 52, it is within the scope of the invention to include any suitable antenna type, such as an antenna that is contained inside the housing 52.

The sensor 50 also includes anchor legs 64 pushed elastically outside the housing 52. The number of anchor legs 64 may vary depending on the degree of desired anchor and the geography of the anatomy in which it should position the sensor 50. The anchor legs 64 are made of wire which uses metallic material with shape memory, such as a nickel titanium alloy (NiTinol). Anchor legs 64 they have a concave configuration with a radius of curvature that curve in the tissue or organ in which the sensor must be anchored 50. Other appropriate configurations for anchor legs 64.

If desired, the sensor 50 is coated with a non-thrombogenic or anticoagulant agent, such as Heparin, with prior to implantation, in order to avoid thrombosis, clot formation, etc.

Figure 3 illustrates an alternative embodiment of sensor 50, which has a tapered end 54 in the housing 52. The tapered end 54 has a piercing tip 55 of the woven, and helical threads 57 formed on the surface tapered end 54 to facilitate anchoring straight from tapered end 54 of housing 52 by threading Direct in the tissue.

Figure 4 illustrates another alternative embodiment. of sensor 50 which includes a plurality of tissue spikes 59, fixed to tapered end 54 of housing 52. Barbs 59 have a piercing tip of the fabric curved out of the tip 55 tissue perforation. Consequently, together with tip 55 of tissue perforation, the tissue spikes 59 grip firmly in the fabric to firmly anchor the housing 52 in the tissue.

As shown in Figure 5, the interior of the housing 52 includes a microprocessor 90, in the form of a microchip, fixed inside one of the interior walls of the housing 52. The cable 70 of the antenna coil 68 is operatively connected to the microprocessor. 90. The microprocessor 90 includes a matrix 92 of photoelectric cells 95 arranged according to a configuration pattern, for example eight stacked rows containing eight photoelectric cells 95 in each of the rows. A reference photoelectric cell 97 is located at one end of the matrix 92, from which it turns out that the matrix 92 has a total of sixty-five photoelectric cells as illustrated in Figure 7. The matrix 92 of cells Photoelectric provides 64 degrees of resolution. The passage distance between each photocell 95 is approximately ¼ the size of a photocell 95. Additionally, the reference photocell 95 has a dimension that is approximately the size of the passage, that is, ¼ the size of a photocell 95, providing that way a resolution that is equal to a movement of ¼ of the
photocell

A light emitting diode (LED) 100, is located operatively connected to microprocessor 90, and is located by above, and separated in parallel with and out of, matrix 92 of photoelectric cells. A shutter 62 is connected to the inner surface of the membrane 56 and extends longitudinally from the membrane 56 inside the housing 52. The shutter 62 has substantially a D-shaped configuration, and extends longitudinally between LED 100 and matrix 92 of photoelectric cells The shutter 62 is made of an alloy of aluminum and positioned in such a way that the planar surface of the shutter 62 faces directly to matrix 92 of cells Photoelectric The plug 62 is fixed to the deformable membrane 56 such that the shutter 62 moves in association with the membrane 56. Accordingly, when membrane 56 deflects towards the interior of the housing 52 (due to the fabric or parameter of monitored or measured organ), shutter 62 extends longitudinally on a number of photoelectric cells 95 of matrix 92, directly related to the movement towards inside the membrane 56 as it is deforming. Likewise, when the membrane 56 is deflected towards the outside of the housing 52, the shutter 62 moves longitudinally out of the end of housing 52 together with membrane 56. In consequently, shutter 62 obscures or blocks a number of 95 photoelectric cells according to the degree of movement of the membrane 56. Thus, when the shutter 62 is placed on a specific number of photoelectric cells 95, prevents the 100 LED light reaches 95 photoelectric cells and affects the signal transmission from these cells 95. This arrangement constitutes an analog-digital (A / D) conversion which is effective in terms of power since there is a count simple of the number of cells that are active or inactive in virtue of measuring the movement of the shutter. Hence, the analog-digital conversion. Consequently, the Microprocessor 90 communicates operatively with membrane 56.

The reference photoelectric cell 97, never is obscured or covered by shutter 62, since it is located at the far end (outer end of the membrane 56) of matrix 92. Shutter 62 and membrane 56 are calibrated to such that with maximum deflection towards the inside of the housing 52, it is obtained as a result that the cell Photoelectric reference 97 is permanently exposed to the LED 100 for use as a reference signal for sensor 50. Even more, the power dissipation of the cell is very low.

As best shown in Figure 6A, the microprocessor 90 is a circuit in which the antenna coil 68 and a resonance capacitor 102, act as a resonant oscillator for sensor 50. The antenna coil 68 receives RF signals transmitted, sent by the reading and loading device 140 of signal, as illustrated in Figures 8 and 9. The RF signal received in antenna coil 68 is a load signal for feed the microprocessor 90. Upon receipt of the signal from RF load, antenna coil 68 and capacitor 102 resonate and charge a charging capacitor 114 through diode 116. After reach a predetermined voltage threshold of approximately 1.2 V, the capacitor 114 feeds the LED 100 and a logic circuit 91 to through control unit 104. With LED 100 power via the charged capacitor 114, the LED emits light to the array 92 photoelectric cells, which is kept under tension negative.

As illustrated in Figure 6B, matrix 92 of photoelectric cells has been designated as P1, P2, ..., P_ {64} and P_ {ref}, respectively. Each cell 95 Photoelectric (P_ {1} -P_ {64}) is connected in parallel with a plurality of comparators 120 designated as C_ {1}, C_ {2}, ..., C_ {64}. The photoelectric cell 97 of reference is operatively connected to each comparator 120 (C_ {1} -C_ {64}) to provide a signal from reference to each comparator 120 compared to the signal received from each respective photoelectric cell 95. The circuit Logic 91 is powered and controlled by control unit 104 and by a clock 106. The control unit 104 is connected to each buyer 120.

A buffer 126 that has a plurality of buffer cells 129 (sixty-four Total buffer cells corresponding to each comparator C1-C64), is connected operatively to comparators 120. Each memory cell 129 intermediate is a flip-flop, or memory cell, which receives a signal from its C1-C64 comparator respective, which results in a binary number that is of sixty-four digits in length (a series of ones or zeros). All buffer cells 129 are filled in a cycle single clock, and each buffer 129 has either a "0" or either a "1" in it. After the sixty-four 129 buffer cells have been filled in with their respective binary number, the digital signal that represents sixty-four bytes is sent to device 140 of reading and loading of signal by means of the control unit 104. After transmission of the digital signal, the control unit 104 it is reset by clock 106 waiting for other signal inputs from the charging and signal reading device 140. The Binary number encryption is provided by the device 140 for reading and signal loading described with greater detail in what follows.

With the filling of sixty-four cells buffer, the digital signal is transmitted from the buffer 126 and activates switch 112 giving as result a transmission of the digital signal from the coil 68 of antenna to the antenna coil 162 of the reading device 140 and signal load.

A main aspect of system 30 of the The present invention is that the sensor 50 is both a Wireless transponder as a low consumption device trained with a fast refresh rate, despite its passive nature, due to the conversion mechanism inherent analog-digital (A / D) used in the sensor 50, for example the array 92 of photoelectric cells, which directly converts deflection of membrane 56 into a signal digital, without power consumption as would be required for a Conventional electronic A / D converter.

Reading Device and Signal Load

As illustrated in Figure 8, the device 140 for reading and signal loading in accordance with this invention, is intended to be used outside the body of a patient or on the outer surface of the patient's body. He reading and signal loading device 140 includes a housing 145, which is an accommodation, which has a display screen 172 of a liquid crystal display (LCD) mounted in an opening of housing 145. The signal reading and loading device, also commonly known as a read / load device, is activated by a power switch or rocker 146 that is extends from the housing 145. The antenna coil 162 communicates operationally with the antenna coil 68 of the sensor 50 by inductance coupling.

As shown in Figure 9, once the Logic circuit 91 transmits the digital signal from sensor 50 to through the sensor antenna coil 68, the constant of Reader / charger antenna coil 162 coupling changes and is detected by a depth detector 168 that is connected operatively to the antenna coil 162 of the reader / charger. He depth detector 168 is sensitized to detect any change in signal amplitude for a change in amplitude so low with 0.01%.

A unit 154 control logic of read / load, is operatively connected to detector 168 of depth to determine the threshold for detector 168 of depth. The logic control unit 154 also includes a power source 151 to power the components of the 140 reader / charger device.

The 150 reader / charger circuit also includes a processing unit 170 operatively connected to the unit 154 control logic. The processing unit 170 Contains the algorithm to convert the received digital signal from sensor 50 (Figure 8) in a parameter measured for the medical parameter, condition or characteristic detected in the sensor 50 implanted. Consequently, the processing unit 170 includes the encryption code for signal encryption digital (sixty-four bit signal) using algorithms of encryption such as exclusive OR (XOR), RSA methods (RSA) Securiry, Inc.), etc.

For example, when the parameter being measuring is the hemodynamic pressure of the blood, within a organ such as a heart chamber, once unit 170 of processing receives the digital signal, unit 170 of Processing, using its algorithm, converts the digital signal (binary number) at a pressure value, using a table of search comparison, or analytical expression that represents the relationship between deflection of shutter 62 in sensor 50, against the external sensor pressure in the membrane 56, which It is given by the expression:

P = (KD 3 / A 2) X 2

where P is the pressure value, D is the thickness of the membrane, A is the radius of the membrane, X is deflection from equilibrium, and K is a constant.

The 172 LCD display is connected operatively to processing unit 170 to display the measured parameter (hemodynamic blood pressure in the example above), converted from the digital signal in time real.

Using read and load device 140 signal outside the patient's body, can be obtained continuous parameter readings (to determine aspects of parameter such as magnitude), for both mean values and active or individual of the sampled parameter.

When the characteristics of a fluid are measured body such as blood, reading and loading device 140 maintains an active reading volume around sensor 50, included in the range of 5 - 25 cm everywhere, and with preference, an active reading volume in the range of approximately 10-15 cm. In addition, with the medical system 30 telemetric, through sensor 50 and reading device 140  and signal load, it is possible to sample multiple readings per second. Preferably, approximately 10-20 are possible readings per second with the present invention.

Other attributes associated with this invention, when used as a pressure monitor in a chamber of the heart, include monitoring a pressure range of +/- 4 kPa (30 mm Hg); an accuracy (at an integration of 5 ms) of +/- 0.133 kPa (1 mm Hg) with repeatability (at an integration of 5 ms) of +/- 0.133 kPa (1 mm Hg). It is important to appreciate that pressure limits can be easily changed by changing the size and dimensions, such as width, of the membrane, without No change in electronics. This is important to allow that the present invention be adapted to various applications while the same design is used.

The control unit 154 is also connected operationally to a sine wave exciter 158, to generate a sine wave signal of approximately 4 to 6 MHz. The signal Sine wave is generated by wave exciter 158 sinusoidal through a capacitor 160, for coil 162 of reader / charger antenna, for transmission or shipment to the coil 68 of sensor antenna 50, in order to power or charge the sensor 50 as described above.

Medical Procedures

As mentioned above, the telemetric medical system 30 in accordance with the present invention It is useful for almost any type of medical procedure of diagnosis in which it is desirable to implant the sensor 50 in some portion of the body, in particular a tissue or an organ of interest. The telemetric medical system 30 according to the invention, allows remote monitoring and diagnosis of a condition of tissue or an organ, being able to quickly sample various parameters or variables of any physical condition inside the patient's body in the place of interest. Since the 30 telemetric medical system is wireless, these types of procedures are performed in a totally non-invasive manner with minimal trauma to the patient.

A particular example for the medical system 30 telemetric according to the present invention, its components and its procedure of use, is included in the field of a failure congestive heart (CHF). CHF is defined as a condition in which a heart 400 (Figure 10) fails to pump Enough blood for other organs of the body. This may be the result of a narrowing of the arteries that supply the blood to the heart muscle (due to a disease of the coronary artery), from a past heart attack, or from a heart attack of myocardium, with scar tissue that interferes with work normal heart muscle, high blood pressure, heart valve disease due to rheumatic fever passed (on valves such as the semilunar valve, the valve tricuspid 417 or mitral valve 418), or for other reasons, first disease of the heart muscle itself, called cardiomyopathy, heart defects present at birth such as congenital heart disease, valve infection of the heart and / or the heart muscle itself (endocarditis and / or myocarditis).

The sickly heart 400 maintains the functioning but not as effectively as it should. People with CHF they can't strain because they lack their breath And they are tired. Since the blood flow to outside the heart 400 is slow, the blood that returns to the heart 400 through the veins it stagnates, causing congestion in the tissues. There is often swelling (edema), more usually on the legs and hips, but also possibly in other parts of the body too. Sometimes it accumulates fluid in the lungs and interferes with breathing, which causes shortness of breath, especially when a person is lying down Heart failure also affects the ability of the kidneys to have sodium and water. Retained water Increase edema

CHF is the most common disease in the States United, and it is estimated that more than 5 million patients suffer from it. One of the most predictive hemodynamic parameters measured in CHF patients, is the blood pressure in atrium 410 left, for example left atrial pressure (LA). Until the date, this parameter is measured using a catheterization of invasive right heart with a special balloon catheter such as the Swan-Gantz catheter.

Consequently, for the moderation of the effects of CHF, it is desirable to measure the blood pressure of a particular chamber (either the right atrium 415, the right ventricle 419, the left atrium 410, or the left ventricle 420) in the heart, using the telemetric medical system 30 according to the present invention
tion.

Consequently, when carrying out a preferred method according to the present invention, the pressure  Blood can be monitored directly in the left atrium 410 of heart 400. Accordingly, it is desirable to implant the sensor 50 in the ovalis pit 407, inside the septum 405.

Regarding the specific anatomy of the septum 405, in approximately 15% of the normal population, the pit ovalis 407 has a hole or opening pre-existing that either stays open, or well it is patent and is normally covered by a small fabric skirt In approximately 85% of the population normal, the ovalis 407 pit is completely occluded, it is say there is no hole in septum 405.

(1) Transcatheter approach

According to the procedure according to the present invention, it has been found that an approximation of transcatheter is particularly useful for the patient population that you already have the pre-existing hole in the pit ovalis 407. Accordingly, for the realization of this method according to the present invention, first of all, a trans-esophageal ultrasonic probe (not shown) in the patient's mouth, and is located in the esophagus. In the greater part of the cases, the ultrasonic probe trans-esophageal is approximately 30 - 35 cm of the mouth, that is, in most cases just above the patient's stomach.

Ultrasonic guided bass trans-esophageal, a wire is inserted (no represented) in the right atrium 415, through a glass appropriate such as the inferior vena cava 408, in which the wire is guided through the ovalis 407 pit by lifting Soft fabric skirt out of patent opening of the ovalis 407 pit. Once the wire has been inserted into through the ovalis 407 pit, the wire is guided to one of the 416 pulmonary veins, for placement of the distal end of the wire so that it is properly positioned, and anchor the wire in the pulmonary vein opening 416. Therefore, it has demonstrated that pulmonary vein 416 is a very anchor point Reliable and firm for the wire.

Once the wire has been positioned properly in the ovalis 407 fossa and has been anchored in vein 416 pulmonary, a catheter sleeve is guided (type "over-the-wire", no represented), on the wire, through the right atrium 415 and of the ovalis pit 407, and is positioned inside the atrium 410 left, for example, very close to vein opening 416 pulmonary.

Once the catheter sleeve has been properly positioned, the wire is removed from the heart 400 of the  patient, and sensor 50 is supplied through the sheath of catheter using one of the many standard devices of catheter-based supply (not shown). Therefore, the sensor 50 can be supplied to the ovalis pit 407 by any of the typical delivery devices based on catheter normally associated with implantable devices pacemakers, electrodes, and occlusion due to septal atrial defect (ASD), etc. Consequently, sensor 50 is available with typical supply devices such as the System of Amplatzer® Supply, manufactured by AGA Medical Corporation of Golden Valley, Minnesota

After placement of the catheter sleeve, the sensor 50 is deployed from the catheter sleeve, inside the ovalis 407 pit, as best illustrated in Figure 11. With the deployment, the sensor 50 uses the anchor legs 64 to anchor the sensor 50 in the septum 405, and occludes the pit opening ovalis 407.

(2) Antegrade Approach

The sensor 50 is placed in the ovalis pit 407 to those patients who do not have an opening pre-existing in the ovalis 407 pit, through means of an antegrade approach. Once again, it is positioned an ultrasonic trans-esophageal probe in the esophagus of the patient, as described above. Under a guided with trans-esophageal ultrasonic imaging, an opening is made in the septum 405 of the ovalis pit 407, with in order to place and accommodate the sensor 50. Thus, it is performed the opening with a standard needle catheter (not shown), such such as the BRK® Transeptal Needle, manufactured by St. Jude Medical,  Inc., from St. Paul, Minnesota. Consequently, under guidance trans-esophageal ultrasonic, the needle catheter is initially located in the right atrium 415, and positioned in the foslis ovalis 407. At that point, the needle tip of the catheter needle penetrates the ovalis 407 fossa, and the catheter is inserted to through the ovalis pit 407 in the left atrium 410 through the newly created opening of the ovalis 407 pit using the catheter needle Once the opening of the ovalis 407 pit has been created, sensor 50 is introduced with the delivery device, such as the delivery device described in what above, and placed in the opening of the ovalis fossa as shown in Figure 11. With the deployment of legs 64 of anchoring, the opening of the ovalis pit 407 is occluded around the housing 52 of the sensor, and the sensor 50 is fixed to the septum 405 in a safe way.

It is important to appreciate that the formation of Ultrasonic trans-esophageal imaging is used both for the transcatheter approach and for the antegrade, as described above, according to each process step of the present invention. Since Any method according to the present invention can be used with the trans-esophageal ultrasonic guide, other imaging modalities can be eliminated such like fluoroscopy As such, the procedures according to The present invention can be carried out in a clinic for outpatients or in the doctor's office as a header procedure. With the elimination of the need for a fluoroscopy, the method according to the present invention it also eliminates the need to carry out the procedure in a catheter lab that only adds time and costs additional to the procedure, and additional time and inconvenience for the patient

Once the sensor 50 has already been implanted in patient sept. 405, standard treatment is provided to the patient to avoid excessive coagulation or endothelialization. For example, a common practice is to prescribe aspirin and / or an anticoagulant such as Heparin for a period of time such About six months.

With any of the procedures described In the foregoing, the sensor 50 is fixed to the septum 405 in order to provide real-time pressure monitoring in the atrium 410 left. Since sensor 50 is a transponder Wireless and a low battery power receiver, sensor 50 it does not impede the natural function of the heart 400 and it truly is minimally invasive

With the use of device 140 of reading and signal loading outside the patient's body, it can obtain continuous pressure readings for both values medium and pulsating pressure in the left atrium 410 provided with the sensor 50.

With the telemetric system 30, the device 140 read and signal load maintains a read volume active around sensor 50 in a range for all surroundings from 5 - 25 cm, and preferably, a volume of active reading in the range of approximately 10-15 cm. In addition, with sensor 50, and with reading device 140 and signal load, it is possible to sample multiple readings per second.  Preferably, 10-20 readings per second are possible with the present invention

Other attributes associated with this invention when used as a pressure monitor in a chamber of the heart, include monitoring a pressure range of plus or minus 4 kPa (30 mm Hg); a precision (to an integration of five ms) of plus or minus 0.133 kPa (1 mm Hg), and repeatability (at an integration of 5 ms) of plus or minus 0.133 kPa (1 mm Hg).

Although preferred embodiments have been described in the foregoing with reference to a system, devices and medical components, and procedures of use, it will be understood that The principles of the present invention may also be used in other types of objects. Preferred embodiments they are mentioned by way of example, and the full scope of the The invention is only limited by the claims.

Claims (17)

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1. A telemetric medical system (30), which understands: a telemetric medical sensor (50) for implantation in the body of a patient for the measurement of a parameter therein, the sensor comprising a housing (52), a membrane (56) at one end of the housing, the membrane being deformable in response to the parameter, and a microchip (90) positioned inside the housing
(52) and operatively communicating with the membrane to transmit a signal indicative of the parameter, and a device (140) for reading and signal loading positionable outside the body of a patient for communication with the sensor (50), comprising the device (140) read and load signal a housing (145); and a circuit (150) inside the housing, the circuit comprising a unit (154) control logic to send a power signal to the sensor (50) to remotely power the sensor, and also to receiving said control logic unit (154) the transmitted signal from the sensor (50), in which the signal transmitted by the sensor (50) is a digital signal, in which the microchip (90) comprises a matrix (92) of photoelectric cells (95), further comprising the LED system (100) to transmit light to cells (95) photoelectric, characterized in that the circuit (150) further comprises a processing unit (170) operatively connected to the control unit (154) to convert the signal transmitted by the sensor (50) into the measured parameter, wherein the sensor (50) further comprises a shutter (62) connected to the membrane (56) and mobile between photoelectric cells (95) and the LED (100) in response to the deformation of the membrane. 2. The system of claim 1, in the that the photoelectric cells (95) are arranged in rows stacked 3. The system of claim 2, in the that the matrix (92) includes a photoelectric cell (97) of reference. 4. The system of claim 3, in the that the reference photoelectric cell (97) is not blocked by the shutter (62). 5. The system of claim 4, in the that the microchip (90) further comprises a plurality of comparators (120) operatively connected to the cells (95) Photoelectric 6. The system of claim 5, in the that the microchip (90) further comprises an intermediate memory (126) operatively connected to the comparators (120), to store and Transmit the digital signal. 7. The system of claim 1, in the that the sensor (50) further comprises an antenna (68) connected Operationally to the microchip (90). 8. The system of claim 7, in the that the antenna (68) is located outside the housing (52). 9. The system of claim 1, in the that the signal reading and loading device (140) includes a antenna coil (162) to send the power signal to the sensor (50), and to receive the digital signal transmitted from the sensor. 10. The system of claim 9, in the that the reading and loading device (140) includes a display (172) for displaying the measured parameter. 11. The system of claim 10, in the that the signal reading and loading device (140) includes a sine wave exciter (158), operatively connected to the control unit (154) to send the power signal to the sensor (50). 12. The system of claim 11, in the that the power signal is a sine wave signal of approximately 4 - 6 MHz. 13. The system of claim 10, in the that the display is an LCD screen (172). 14. The system of claim 9, in the that the processing unit (170) decodes the signal transmitted. 15. The system of claim 14, in the that the signal reading and loading device (140) includes a depth detector (168) to receive the transmitted signal. 16. The system of claim 15, in the that the signal reading and loading device (140) includes a power supply (151) operatively connected to the circuit (150). 17. The system of claim 16, in the that the signal reading and loading device (140) includes a power switch (146) to activate and deactivate the device (140).